A Michael Equilibration Model To Control Site Selectivity in the Condensation toward Aminopyrazoles

Org Lett. 2015 Jun 19;17(12):2964-7. doi: 10.1021/acs.orglett.5b01248. Epub 2015 Jun 1.

Abstract

A Michael equilibration model is presented to provide for site-selective pyrazole condensations between alkoxyacrylonitriles and hydrazines. Both pyrazole isomers were accessed with high selectivity by employment of kinetically or thermodynamically controlled conditions. Substrate scope and identification of Michael intermediates, as well as competitive pathways, support the presented mechanistic proposal. Sandmeyer derivatization provided site-selective access to fully substituted pyrazoles.

MeSH terms

  • Kinetics
  • Models, Molecular
  • Molecular Structure
  • Pyrazoles / chemical synthesis*
  • Pyrazoles / chemistry
  • Thermodynamics

Substances

  • Pyrazoles